Electric-light fixture



Jan. 7, 1930. L. A. HOFFMAN ELECTRIC LIGHT FIXTURE Filed Sept. 20, 1926 poocnoooc Patented Jan. 7, 1930 UNITED LOUIS A HOFFMAN, OF CHICAGO, ILLINOIS ELECTRIC-LIGHT frrxrrumi Application led September 20, 19,26, .Serial No. 136,398.

This yinvention relates to improvements in electric light fixtures, and refers more particularly to improved means of mounting a lamp socket on a support in such a manner that the socket may be quickly adjusted to extend at varying angles in relation to its suport.

p One of the objects of the invention is to provide an improved mounting means of this '-0 character comprising a ball joint which permits the lamp socket to have a universal swinging movement in all directions over a wide range.

Another object is lto provide an'adjustable mounting means which is constructed as a part of the lamp socket itself. j

A further object is to provide means for limiting the rotational adjustment of the lamp socket about its axis, so as to insure against twisting olf the wires leading into the socket.

In carrying out these objects I employ a ball tting in a recess in the normally closed end of the lamp socket, the ball having an attaching stem to be secured to a support,

and I provide means within the lamp socket engaging said ball to hold it in place and to limit the rotational adjustment of the socket While permitting the socket to be pivoted in all directions uponthe ball, so that.

the electric lamp in the socket may be adjusted by the user to a desired position las, for example, to accommodate the shape of the lamp shade or for other purposes.

Referring to the accompanying drawings:

Figure 1 is a fragmentary/view ofa floor lamp having a pair of light sockets mounted thereon by means of a preferred form of this invention.

Fig. 2 is an enlarged fragmentary elevation of the preferred form of the invention, the cap thereof being shown in section.

Fig. 3 is a plan view ofthe formshoivn in Fig. 2, a part of the capbeing broken away. Fig. 4 is an lenlarged perspective of the ball member of this device.

Fig. 5 is `an enlarged view of a light socket showing Vin longitudinal section a modification of the means for` .adjustably securing the socket to the light fixture.

Fig. 6 is an end section of the modification taken on a line 6-6 of Fig. 5.

Although the invention is susceptible of various modifications and alternative constructions, I have shown and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention .to the specific form disclosed, but intend to cover all modifications and alternative constructions fall` ing within the spirit and scope of the invention as expressed in the appended claims.

It will be readily understood that Ithis method of mounting a light socket on a vfixture may apply to any type Vof fixture. For, -t5

"the purpose .of illustrating the invention,`l

however, I have shown a floor lamp o f an ordinary construction having an upright standard V5 upon the ,upper end of which `is secured an outlet cup k6 to whicha pair ot To sockets 7 are attached.

The customary manner of securing the sockets 7 to the outlet cu-p 6 provides a rigid junction therebetween. I have provided what is, in effect, a ball andsocket joint be- 1u tween the outlet .cup and the light sockets, so j that the sockets may have a universal swinging movement in all .directions thereby permitting ready adjustment overa wide range. This o ining means comprises a ball memberV se 8 (FigsQ, i and 5) preferably in the form of` a short .tubular member, one end of which is turned to provide a substantially spherical surface .or ball 9. The other end ofthe ball member providing; an lattaching stem 10. is externally screw theaded and -an intermedi!"Y ate collar 11 separates the stem 10 from the ball 9.- 'lhe outlet cup-'6, from Which the yelectric lead wires are distributed, is provided with suitable apertures kto receive .the stem ee 10. yThe .collar -ll bears 'externally;against"` the outletcup 6 `and =cooperates witha ynut l2 to secure the cup and the ball memberrigidly together.

The socketsV 7 are of the usual @Cmmercial 4e5 Ltype in which one .end is normallyclosed by means .of a cap 13.. Inthe present instance, this cap is provided Wit'hJa `central recess 14:, the edges of which ,are turned to provide vasnug bearing surface for the ball 9. y).00

The recess 14 is of suchy sizeV Vas to prevent the passage of the ball therethrough.

To provide a socket in which the ball 9 may turn universally, a clamping member such as a plate 15 having a cent-ral opening 16 corresponding to the recess 14 in the cap is secured in the'cap in a suitable manner. The platev 15 may, as shown in Fig. 2, conform to the interior contour of the cap or may, as shown in Figs. 5 and 6, have the form of a flat plate. The `plate may be secured in the cap as by means of bolts V (Fig. 3), or as shown in Fig. 6, by means of a lug 17 on one edge of the plate and a screw threadedv hole 18 disposed diagonally thereto. Lug 17 is arranged to enter a suitably Vpositioned Y hole 19 in the cap 13 and a bolt 20 passing the plate 15 with the ball through the' cap into the threadedV opening 18 in the plate secures the plate to the cap.

The arrangement of parts is such that in the assembled unit the cap 13 will contact on the surface of one hemisphere of the ball 9 while the plate `15 will bear on the surface f of the other hemisphere, thus holding the ball firmly against displacement, but permitting free universal movement. By means of the bolts 20 or 20"I the frictional engagement of 9 may be adjustably regulated.

As shown in Figs. 2 and 5, a pair of lead wiresl 21 extend from a source of current Vthrough the ball member to suitable contacts thereabout. The bearing surface which engages the outer hemisphere of the ball 9 isV provided by means `of an insert or strengthening plate 23 positioned between thecap 13 and the plate 15 and held rigidly therewith by means of the bolts 20. A stop member Vin the' form of a semicircular bar 24, the ends of( which are turned inwardly as at 25', is secured between the insert plate 23 and the cap-13 in such position thatv it rest-s withinthe groove vprovided with a slot 26 into which the ends 25` ofthe bar 24 are arranged to extend. The bar'24being held. rigidly between the insertv plate 23 and the capjl will permit auniversal all inany direction, but

ment-relative to the capi i It will be apparentthat it is-possible to construct the cap 13 of 'such strength as to render the use of the inl sertplate 23 unnecessary. In such event the lshoulder 22 would also be formedto provide Vthrough said supporting wall, 1.a nut on said stemv for clamping'the balltO said wall, saidY v .l j n vrsocket being supported byfs'aid ball and perprovided by the shoulder 22. The ball'9 1s engagin cap and the ball and the bar 24 would be secured between the cap 13 and the late 15.

A modification of the means by w ich the axial rotation of the ball is limited comprises a rigid member such as a bar 27 fitting in the slot 26 formed in the ball 9 and extending laterally beyond the edges of the plate 15. Each end of the bar 27 is bent outwardly past the surface of the plate 15 and at certain positions of the plate relative to the ball the bent ends of the bar will contact the edges of the plate. Thus upon rotation of the socket about the balllineither direction, the bar 27 in the `ball 9 will contact the edgesof theY plate 15 in the socket cap 13 to prevent further rotation thereof.` In this modification the use of the strengthening plate23 is unnecessary. Y v

It will readily be seen from Vthe foregoing description that I have provided a means of mounting a light socket on a fixture-which is simple and'efiicient, which permits an adjustable universal swinging movement of the socket on the fixture and one in which only a limited rotational movement is allowed.

The mounting means is a part ofthe light socket itself which is conducive to compactness and neatness 1n appearance and provides a socket which Vcan be mounted onmany varying kinds of supports.

I claim as my invention: y 1. An electric light fixture com rising, in

combination, a support, a lamp soc et, means for attaching said socket to said support includmg a ball engaging in a recess in the end of said socket, said `ball having a stem projecting away v,from said'socket and attached to said support, a plate secured within said socket and engaging said ball to hold said ball in place and to hold frictionally the socket in various angles of adjustment about said ball, and means within said socket engaging said ball to limit the axial rotation ofv said socket about said ball. Y

2. -An electric light fixture comprising, in j susL said socket and having a stem projecting a mitted to move about said ball asa pivotin all directions, and means withinsaid socket` y Y kprojecting vfrom said support, a lamp socket having a kportion embracingsaid ball to be supported thereby for Vuniversal swinging limit "the axial .rotationV movement about said ball, and means` in said socket adapted to limit axial rotation of said socket on saidball, comprising a Vmember fixed to said socket and associated with saidi13'0v ball, said member and said ball having an engagement with each other at the limits of rotational movement of the socket.

4. An electric light fixture comprising, in combination, a support, a lamp socket, means for attaching said socket to said support including a ball engaging in a recess in the end of said socket, said ball having a stem projecting away from said socket and attached to said support, a plate secured within said socket and engaging said ball to hold said ball in place, and means yto limit axial rotation of said socket' on said ball, said means being located within said socket and comprising a stop member extending between said socket and said ball operable to limit the rotational movement of the socket. i

5. A n electric light fixture comprising, in combination, a ball, a light socket adapted to support a light and to embrace said ball, clamping means in said light socket arranged frictionally to engage said ball to permit free universal movement of said light socket relative to said ball, and means secured within said light socket adapted to limit relative axial rotation between said ball and said light socket.

6. An electric light fixture comprising, in combination, a ball, a light socket adapted to support a light and recessed to embrace said ball, a clamping plate in said light socket arranged frictionally to engage said ball to permit free universal movement of said light socket relative to said ball, and means held in said light socket by said clamping plate and engaging said ball to limit axial relative rotation between said ball and said light socket.

7. An electric light ixturecomprising, in combination, a support, a ball member rigid with said support, a lamp socket having a part embracing said ball member to be supported thereby for swinging movement about said ball, and means to limit axial rotation of said socket on said ball, said means being located within said socket, comprising a plate arranged to bear against the inner hemisphere of said ball, a second plate positioned between said first mentioned plate and said socket, and means associated between one of said plates and said socket arranged to engage said ball at the limits of rotational movement in the socket.

In testimony whereof, I have hereunto affixed my signature.

LOUIS A. HOFFMAN. 

